Sometimes the system is designed to overflow when it rains a lot. Those systems connect the stormwater and wastewater collection and are called Combined Sewer Systems. When they overflow, they are called Combined Sewer Overflows. Cities across the country are required to eliminate these occasional raw sewage overflows and are making significant investments to either disconnect the two systems or increase the capacity of the system to handle the influx of heavy rains.
Even when the systems for wastewater and stormwater are not connected, the raw sewage can still end up in our waters due to the leaking infrastructure. When the systems called Separated Sewer Systems are overwhelmed, the Separated Sewer Overflows occur at manholes in the street, sometimes through relief valves designed in the system to flow into the rivers, and sometimes, the overwhelmed system backs up into basements and backyards of homeowners at the low point in the system. These overflows also require investment in infrastructure to solve the problem. Although they are violations to the operating permits, these system upgrades have not received the same amount of attention as the Combined Sewer Overflows.
Realities we face. First, the cost of such upgrades are borne by the community and often the greatest needs are in lower income or communities of color that have been overlooked for investment and are not able to pay for these upgrades.
Second, the increase in frequency and intensity of storms bringing much more rain due to climate change makes the need for these infrastructure improvements more urgent.
Third, the private homeowner sewage backups are often experienced in lower income, low lying communities. Cleaning up from a sewage back up is expensive, there are many health concerns, and the connection to the broader community sewage problems may not be immediately obvious or easy to demonstrate. Learn what is happening Baltimore.